Development of Diabetes in Chinese with the Metabolic Syndrome - a Six Year Prospective Study

Abstract

Objective: We investigated the association of the metabolic syndrome with new-onset diabetes mellitus in the Hong Kong Cardiovascular Risk Factor Prevalence Survey cohort.

Methods: We followed up 1,679 subjects without diabetes at baseline. Those previously diagnosed to have diabetes or were on drug treatment were considered diabetic. The remaining subjects underwent a 75g oral glucose tolerance test. Diabetes was defined by a plasma glucose ≥ 7.0 mmol/l in fasting and/or ≥ 11.1 mmol/l at 2 hours.

Results: The prevalence of the metabolic syndrome at baseline was 14.5% and 11.4% respectively according to US National Cholesterol Education Program (NCEP) and International Diabetes Federation (IDF) criteria. After a median of 6.4 years, there were 66 and 54 new cases of diabetes in men and women, respectively. The metabolic syndrome at baseline predicted incident diabetes. The hazard ratios for the NCEP and IDF definitions of the syndrome were 4.1 [95% CI: 2.8-6.0] and 3.5 [95% CI: 2.3-5.2] respectively. The hazard ratios for fasting plasma glucose ≥ 6.1 or 5.6 mmol/L were 6.9 [95%CI: 4.1-11.5] and 4.1 [95%CI: 2.8-6.0] respectively. The NCEP and IDF criteria had 41.9% and 31.7% sensitivity and 87.5% and 90.2% specificity, respectively. Their positive predictive values were low, around 20%, but their negative predictive values were around 95%.

Conclusions: The metabolic syndrome, particularly its component, elevated fasting plasma glucose, predicts diabetes mellitus in Chinese. A person without the metabolic syndrome is unlikely to develop diabetes, but one who has it should have therapeutic lifestyle changes and periodic fasting glucose measurements to detect new-onset diabetes.